feat(highlight): add treesitter context padding from disk
Problem: treesitter parses each diff hunk in isolation, so incomplete syntax constructs at hunk boundaries (e.g., a function definition with no body) produce ERROR nodes and drop captures. Solution: read N lines from the on-disk file before/after each hunk and prepend/append them as unmapped padding lines. The line_map guard in highlight_treesitter skips extmarks for unmapped lines, so padding provides syntax context without visual output. Controlled by highlights.context (default 25, 0 to disable). Also applies to the vim syntax fallback path via a leading_offset filter.
This commit is contained in:
parent
ba1f830629
commit
2e1ebdee03
7 changed files with 308 additions and 24 deletions
10
README.md
10
README.md
|
|
@ -41,12 +41,10 @@ luarocks install diffs.nvim
|
|||
|
||||
## Known Limitations
|
||||
|
||||
- **Incomplete syntax context**: Treesitter parses each diff hunk in isolation
|
||||
without surrounding code context. When a hunk shows lines added to an existing
|
||||
block (e.g., adding a plugin inside `return { ... }`), the parser doesn't see
|
||||
the `return` statement and may produce incorrect highlighting. This is
|
||||
inherent to parsing code fragments—no diff tooling solves this without
|
||||
significant complexity.
|
||||
- **Incomplete syntax context**: Treesitter parses each diff hunk in isolation.
|
||||
To improve accuracy, `diffs.nvim` reads lines from disk before and after each
|
||||
hunk for parsing context (controlled by `highlights.context`, default 25).
|
||||
This resolves most boundary issues. Set `highlights.context = 0` to disable.
|
||||
|
||||
- **Syntax flashing**: `diffs.nvim` hooks into the `FileType fugitive` event
|
||||
triggered by `vim-fugitive`, at which point the buffer is preliminarily
|
||||
|
|
|
|||
|
|
@ -56,6 +56,7 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
|
|||
highlights = {
|
||||
background = true,
|
||||
gutter = true,
|
||||
context = 25,
|
||||
treesitter = {
|
||||
enabled = true,
|
||||
max_lines = 500,
|
||||
|
|
@ -113,6 +114,16 @@ Configuration is done via `vim.g.diffs`. Set this before the plugin loads:
|
|||
Highlight line numbers with matching colors.
|
||||
Only visible if line numbers are enabled.
|
||||
|
||||
{context} (integer, default: 25)
|
||||
Number of lines to read from the source file
|
||||
before and after each hunk for syntax parsing
|
||||
context. Improves accuracy at hunk boundaries
|
||||
where incomplete constructs (e.g., a function
|
||||
definition with no body) would otherwise confuse
|
||||
the parser. Set to 0 to disable. Lines are read
|
||||
from disk with early exit — cost scales with the
|
||||
context value, not file size.
|
||||
|
||||
{treesitter} (table, default: see below)
|
||||
Treesitter highlighting options.
|
||||
See |diffs.TreesitterConfig| for fields.
|
||||
|
|
@ -305,14 +316,15 @@ KNOWN LIMITATIONS *diffs-limitations*
|
|||
|
||||
Incomplete Syntax Context ~
|
||||
*diffs-syntax-context*
|
||||
Treesitter parses each diff hunk in isolation without surrounding code
|
||||
context. When a hunk shows lines added to an existing block (e.g., adding a
|
||||
plugin inside `return { ... }`), the parser doesn't see the `return`
|
||||
statement and may produce incorrect or unusual highlighting.
|
||||
Treesitter parses each diff hunk in isolation. To provide surrounding code
|
||||
context, diffs.nvim reads lines from disk before and after each hunk
|
||||
(controlled by `highlights.context`, default 25). This resolves most boundary
|
||||
issues where incomplete constructs (e.g., a function definition at the edge
|
||||
of a hunk with no body) would confuse the parser.
|
||||
|
||||
This is inherent to parsing code fragments. No diff tooling solves this
|
||||
problem without significant complexity—the parser simply doesn't have enough
|
||||
information to understand the full syntactic structure.
|
||||
Set `highlights.context = 0` to disable context padding and restore the
|
||||
previous behavior. In rare cases, context padding may not help if the
|
||||
relevant surrounding code is very far from the hunk boundaries.
|
||||
|
||||
Syntax Highlighting Flash ~
|
||||
*diffs-flash*
|
||||
|
|
|
|||
|
|
@ -3,6 +3,33 @@ local M = {}
|
|||
local dbg = require('diffs.log').dbg
|
||||
local diff = require('diffs.diff')
|
||||
|
||||
---@param filepath string
|
||||
---@param from_line integer
|
||||
---@param count integer
|
||||
---@return string[]
|
||||
local function read_line_range(filepath, from_line, count)
|
||||
if count <= 0 then
|
||||
return {}
|
||||
end
|
||||
local f = io.open(filepath, 'r')
|
||||
if not f then
|
||||
return {}
|
||||
end
|
||||
local result = {}
|
||||
local line_num = 0
|
||||
for line in f:lines() do
|
||||
line_num = line_num + 1
|
||||
if line_num >= from_line then
|
||||
table.insert(result, line)
|
||||
if #result >= count then
|
||||
break
|
||||
end
|
||||
end
|
||||
end
|
||||
f:close()
|
||||
return result
|
||||
end
|
||||
|
||||
local PRIORITY_CLEAR = 198
|
||||
local PRIORITY_SYNTAX = 199
|
||||
local PRIORITY_LINE_BG = 200
|
||||
|
|
@ -177,8 +204,9 @@ end
|
|||
---@param hunk diffs.Hunk
|
||||
---@param code_lines string[]
|
||||
---@param covered_lines? table<integer, true>
|
||||
---@param leading_offset? integer
|
||||
---@return integer
|
||||
local function highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines)
|
||||
local function highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines, leading_offset)
|
||||
local ft = hunk.ft
|
||||
if not ft then
|
||||
return 0
|
||||
|
|
@ -188,6 +216,8 @@ local function highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines)
|
|||
return 0
|
||||
end
|
||||
|
||||
leading_offset = leading_offset or 0
|
||||
|
||||
local scratch = vim.api.nvim_create_buf(false, true)
|
||||
vim.api.nvim_buf_set_lines(scratch, 0, -1, false, code_lines)
|
||||
vim.api.nvim_set_option_value('bufhidden', 'wipe', { buf = scratch })
|
||||
|
|
@ -214,17 +244,21 @@ local function highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines)
|
|||
|
||||
vim.api.nvim_buf_delete(scratch, { force = true })
|
||||
|
||||
local hunk_line_count = #hunk.lines
|
||||
local extmark_count = 0
|
||||
for _, span in ipairs(spans) do
|
||||
local buf_line = hunk.start_line + span.line - 1
|
||||
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, span.col_start, {
|
||||
end_col = span.col_end,
|
||||
hl_group = span.hl_name,
|
||||
priority = PRIORITY_SYNTAX,
|
||||
})
|
||||
extmark_count = extmark_count + 1
|
||||
if covered_lines then
|
||||
covered_lines[buf_line] = true
|
||||
local adj = span.line - leading_offset
|
||||
if adj >= 1 and adj <= hunk_line_count then
|
||||
local buf_line = hunk.start_line + adj - 1
|
||||
pcall(vim.api.nvim_buf_set_extmark, bufnr, ns, buf_line, span.col_start, {
|
||||
end_col = span.col_end,
|
||||
hl_group = span.hl_name,
|
||||
priority = PRIORITY_SYNTAX,
|
||||
})
|
||||
extmark_count = extmark_count + 1
|
||||
if covered_lines then
|
||||
covered_lines[buf_line] = true
|
||||
end
|
||||
end
|
||||
end
|
||||
|
||||
|
|
@ -255,6 +289,20 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
|
|||
---@type table<integer, true>
|
||||
local covered_lines = {}
|
||||
|
||||
local context = opts.highlights.context or 0
|
||||
local leading = {}
|
||||
local trailing = {}
|
||||
if (use_ts or use_vim) and context > 0 and hunk.file_new_start and hunk.repo_root then
|
||||
local filepath = vim.fs.joinpath(hunk.repo_root, hunk.filename)
|
||||
local lead_from = math.max(1, hunk.file_new_start - context)
|
||||
local lead_count = hunk.file_new_start - lead_from
|
||||
if lead_count > 0 then
|
||||
leading = read_line_range(filepath, lead_from, lead_count)
|
||||
end
|
||||
local trail_from = hunk.file_new_start + (hunk.file_new_count or 0)
|
||||
trailing = read_line_range(filepath, trail_from, context)
|
||||
end
|
||||
|
||||
local extmark_count = 0
|
||||
if use_ts then
|
||||
---@type string[]
|
||||
|
|
@ -266,6 +314,11 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
|
|||
---@type table<integer, integer>
|
||||
local old_map = {}
|
||||
|
||||
for _, pad_line in ipairs(leading) do
|
||||
table.insert(new_code, pad_line)
|
||||
table.insert(old_code, pad_line)
|
||||
end
|
||||
|
||||
for i, line in ipairs(hunk.lines) do
|
||||
local prefix = line:sub(1, 1)
|
||||
local stripped = line:sub(2)
|
||||
|
|
@ -284,6 +337,11 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
|
|||
end
|
||||
end
|
||||
|
||||
for _, pad_line in ipairs(trailing) do
|
||||
table.insert(new_code, pad_line)
|
||||
table.insert(old_code, pad_line)
|
||||
end
|
||||
|
||||
extmark_count = highlight_treesitter(bufnr, ns, new_code, hunk.lang, new_map, 1, covered_lines)
|
||||
extmark_count = extmark_count
|
||||
+ highlight_treesitter(bufnr, ns, old_code, hunk.lang, old_map, 1, covered_lines)
|
||||
|
|
@ -305,10 +363,16 @@ function M.highlight_hunk(bufnr, ns, hunk, opts)
|
|||
elseif use_vim then
|
||||
---@type string[]
|
||||
local code_lines = {}
|
||||
for _, pad_line in ipairs(leading) do
|
||||
table.insert(code_lines, pad_line)
|
||||
end
|
||||
for _, line in ipairs(hunk.lines) do
|
||||
table.insert(code_lines, line:sub(2))
|
||||
end
|
||||
extmark_count = highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines)
|
||||
for _, pad_line in ipairs(trailing) do
|
||||
table.insert(code_lines, pad_line)
|
||||
end
|
||||
extmark_count = highlight_vim_syntax(bufnr, ns, hunk, code_lines, covered_lines, #leading)
|
||||
end
|
||||
|
||||
if
|
||||
|
|
|
|||
|
|
@ -14,6 +14,7 @@
|
|||
---@class diffs.Highlights
|
||||
---@field background boolean
|
||||
---@field gutter boolean
|
||||
---@field context integer
|
||||
---@field treesitter diffs.TreesitterConfig
|
||||
---@field vim diffs.VimConfig
|
||||
---@field intra diffs.IntraConfig
|
||||
|
|
@ -80,6 +81,7 @@ local default_config = {
|
|||
highlights = {
|
||||
background = true,
|
||||
gutter = true,
|
||||
context = 25,
|
||||
treesitter = {
|
||||
enabled = true,
|
||||
max_lines = 500,
|
||||
|
|
@ -231,6 +233,7 @@ local function init()
|
|||
vim.validate({
|
||||
['highlights.background'] = { opts.highlights.background, 'boolean', true },
|
||||
['highlights.gutter'] = { opts.highlights.gutter, 'boolean', true },
|
||||
['highlights.context'] = { opts.highlights.context, 'number', true },
|
||||
['highlights.treesitter'] = { opts.highlights.treesitter, 'table', true },
|
||||
['highlights.vim'] = { opts.highlights.vim, 'table', true },
|
||||
['highlights.intra'] = { opts.highlights.intra, 'table', true },
|
||||
|
|
@ -291,6 +294,9 @@ local function init()
|
|||
if opts.debounce_ms and opts.debounce_ms < 0 then
|
||||
error('diffs: debounce_ms must be >= 0')
|
||||
end
|
||||
if opts.highlights and opts.highlights.context and opts.highlights.context < 0 then
|
||||
error('diffs: highlights.context must be >= 0')
|
||||
end
|
||||
if
|
||||
opts.highlights
|
||||
and opts.highlights.treesitter
|
||||
|
|
|
|||
|
|
@ -8,6 +8,11 @@
|
|||
---@field lines string[]
|
||||
---@field header_start_line integer?
|
||||
---@field header_lines string[]?
|
||||
---@field file_old_start integer?
|
||||
---@field file_old_count integer?
|
||||
---@field file_new_start integer?
|
||||
---@field file_new_count integer?
|
||||
---@field repo_root string?
|
||||
|
||||
local M = {}
|
||||
|
||||
|
|
@ -132,6 +137,14 @@ function M.parse_buffer(bufnr)
|
|||
local header_start = nil
|
||||
---@type string[]
|
||||
local header_lines = {}
|
||||
---@type integer?
|
||||
local file_old_start = nil
|
||||
---@type integer?
|
||||
local file_old_count = nil
|
||||
---@type integer?
|
||||
local file_new_start = nil
|
||||
---@type integer?
|
||||
local file_new_count = nil
|
||||
|
||||
local function flush_hunk()
|
||||
if hunk_start and #hunk_lines > 0 then
|
||||
|
|
@ -143,6 +156,11 @@ function M.parse_buffer(bufnr)
|
|||
header_context = hunk_header_context,
|
||||
header_context_col = hunk_header_context_col,
|
||||
lines = hunk_lines,
|
||||
file_old_start = file_old_start,
|
||||
file_old_count = file_old_count,
|
||||
file_new_start = file_new_start,
|
||||
file_new_count = file_new_count,
|
||||
repo_root = repo_root,
|
||||
}
|
||||
if hunk_count == 1 and header_start and #header_lines > 0 then
|
||||
hunk.header_start_line = header_start
|
||||
|
|
@ -154,6 +172,10 @@ function M.parse_buffer(bufnr)
|
|||
hunk_header_context = nil
|
||||
hunk_header_context_col = nil
|
||||
hunk_lines = {}
|
||||
file_old_start = nil
|
||||
file_old_count = nil
|
||||
file_new_start = nil
|
||||
file_new_count = nil
|
||||
end
|
||||
|
||||
for i, line in ipairs(lines) do
|
||||
|
|
@ -174,6 +196,13 @@ function M.parse_buffer(bufnr)
|
|||
elseif line:match('^@@.-@@') then
|
||||
flush_hunk()
|
||||
hunk_start = i
|
||||
local hs, hc, hs2, hc2 = line:match('^@@ %-(%d+),?(%d*) %+(%d+),?(%d*) @@')
|
||||
if hs then
|
||||
file_old_start = tonumber(hs)
|
||||
file_old_count = tonumber(hc) or 1
|
||||
file_new_start = tonumber(hs2)
|
||||
file_new_count = tonumber(hc2) or 1
|
||||
end
|
||||
local prefix, context = line:match('^(@@.-@@%s*)(.*)')
|
||||
if context and context ~= '' then
|
||||
hunk_header_context = context
|
||||
|
|
|
|||
|
|
@ -37,6 +37,7 @@ describe('highlight', function()
|
|||
highlights = {
|
||||
background = false,
|
||||
gutter = false,
|
||||
context = 0,
|
||||
treesitter = {
|
||||
enabled = true,
|
||||
max_lines = 500,
|
||||
|
|
@ -1055,6 +1056,99 @@ describe('highlight', function()
|
|||
assert.is_true(min_line_bg < min_char_bg)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
|
||||
it('context padding produces no extmarks on padding lines', function()
|
||||
local repo_root = '/tmp/diffs-test-context'
|
||||
vim.fn.mkdir(repo_root, 'p')
|
||||
|
||||
local f = io.open(repo_root .. '/test.lua', 'w')
|
||||
f:write('local M = {}\n')
|
||||
f:write('function M.hello()\n')
|
||||
f:write(' return "hi"\n')
|
||||
f:write('end\n')
|
||||
f:write('return M\n')
|
||||
f:close()
|
||||
|
||||
local bufnr = create_buffer({
|
||||
'@@ -3,1 +3,2 @@',
|
||||
' return "hi"',
|
||||
'+"bye"',
|
||||
})
|
||||
|
||||
local hunk = {
|
||||
filename = 'test.lua',
|
||||
lang = 'lua',
|
||||
start_line = 1,
|
||||
lines = { ' return "hi"', '+"bye"' },
|
||||
file_old_start = 3,
|
||||
file_old_count = 1,
|
||||
file_new_start = 3,
|
||||
file_new_count = 2,
|
||||
repo_root = repo_root,
|
||||
}
|
||||
|
||||
highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ highlights = { context = 25 } }))
|
||||
|
||||
local extmarks = get_extmarks(bufnr)
|
||||
for _, mark in ipairs(extmarks) do
|
||||
local row = mark[2]
|
||||
assert.is_true(row >= 1 and row <= 2)
|
||||
end
|
||||
|
||||
delete_buffer(bufnr)
|
||||
os.remove(repo_root .. '/test.lua')
|
||||
vim.fn.delete(repo_root, 'rf')
|
||||
end)
|
||||
|
||||
it('context = 0 matches behavior without padding', function()
|
||||
local bufnr = create_buffer({
|
||||
'@@ -1,1 +1,2 @@',
|
||||
' local x = 1',
|
||||
'+local y = 2',
|
||||
})
|
||||
|
||||
local hunk = {
|
||||
filename = 'test.lua',
|
||||
lang = 'lua',
|
||||
start_line = 1,
|
||||
lines = { ' local x = 1', '+local y = 2' },
|
||||
file_new_start = 1,
|
||||
file_new_count = 2,
|
||||
repo_root = '/nonexistent',
|
||||
}
|
||||
|
||||
highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ highlights = { context = 0 } }))
|
||||
|
||||
local extmarks = get_extmarks(bufnr)
|
||||
assert.is_true(#extmarks > 0)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
|
||||
it('gracefully handles missing file for context padding', function()
|
||||
local bufnr = create_buffer({
|
||||
'@@ -1,1 +1,2 @@',
|
||||
' local x = 1',
|
||||
'+local y = 2',
|
||||
})
|
||||
|
||||
local hunk = {
|
||||
filename = 'test.lua',
|
||||
lang = 'lua',
|
||||
start_line = 1,
|
||||
lines = { ' local x = 1', '+local y = 2' },
|
||||
file_new_start = 1,
|
||||
file_new_count = 2,
|
||||
repo_root = '/nonexistent/path',
|
||||
}
|
||||
|
||||
assert.has_no.errors(function()
|
||||
highlight.highlight_hunk(bufnr, ns, hunk, default_opts({ highlights = { context = 25 } }))
|
||||
end)
|
||||
|
||||
local extmarks = get_extmarks(bufnr)
|
||||
assert.is_true(#extmarks > 0)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
end)
|
||||
|
||||
describe('diff header highlighting', function()
|
||||
|
|
@ -1086,6 +1180,7 @@ describe('highlight', function()
|
|||
highlights = {
|
||||
background = false,
|
||||
gutter = false,
|
||||
context = 0,
|
||||
treesitter = { enabled = true, max_lines = 500 },
|
||||
vim = { enabled = false, max_lines = 200 },
|
||||
},
|
||||
|
|
@ -1242,6 +1337,7 @@ describe('highlight', function()
|
|||
highlights = {
|
||||
background = false,
|
||||
gutter = false,
|
||||
context = 0,
|
||||
treesitter = { enabled = true, max_lines = 500 },
|
||||
vim = { enabled = false, max_lines = 200 },
|
||||
},
|
||||
|
|
|
|||
|
|
@ -421,5 +421,84 @@ describe('parser', function()
|
|||
os.remove(file_path)
|
||||
vim.fn.delete(repo_root, 'rf')
|
||||
end)
|
||||
|
||||
it('extracts file line numbers from @@ header', function()
|
||||
local bufnr = create_buffer({
|
||||
'M lua/test.lua',
|
||||
'@@ -1,3 +1,4 @@',
|
||||
' local M = {}',
|
||||
'+local new = true',
|
||||
' return M',
|
||||
})
|
||||
local hunks = parser.parse_buffer(bufnr)
|
||||
|
||||
assert.are.equal(1, #hunks)
|
||||
assert.are.equal(1, hunks[1].file_old_start)
|
||||
assert.are.equal(3, hunks[1].file_old_count)
|
||||
assert.are.equal(1, hunks[1].file_new_start)
|
||||
assert.are.equal(4, hunks[1].file_new_count)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
|
||||
it('extracts large line numbers from @@ header', function()
|
||||
local bufnr = create_buffer({
|
||||
'M lua/test.lua',
|
||||
'@@ -100,20 +200,30 @@',
|
||||
' local M = {}',
|
||||
})
|
||||
local hunks = parser.parse_buffer(bufnr)
|
||||
|
||||
assert.are.equal(1, #hunks)
|
||||
assert.are.equal(100, hunks[1].file_old_start)
|
||||
assert.are.equal(20, hunks[1].file_old_count)
|
||||
assert.are.equal(200, hunks[1].file_new_start)
|
||||
assert.are.equal(30, hunks[1].file_new_count)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
|
||||
it('defaults count to 1 when omitted in @@ header', function()
|
||||
local bufnr = create_buffer({
|
||||
'M lua/test.lua',
|
||||
'@@ -1 +1 @@',
|
||||
' local M = {}',
|
||||
})
|
||||
local hunks = parser.parse_buffer(bufnr)
|
||||
|
||||
assert.are.equal(1, #hunks)
|
||||
assert.are.equal(1, hunks[1].file_old_start)
|
||||
assert.are.equal(1, hunks[1].file_old_count)
|
||||
assert.are.equal(1, hunks[1].file_new_start)
|
||||
assert.are.equal(1, hunks[1].file_new_count)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
|
||||
it('stores repo_root on hunk when available', function()
|
||||
local bufnr = create_buffer({
|
||||
'M lua/test.lua',
|
||||
'@@ -1,3 +1,4 @@',
|
||||
' local M = {}',
|
||||
'+local new = true',
|
||||
' return M',
|
||||
})
|
||||
vim.api.nvim_buf_set_var(bufnr, 'diffs_repo_root', '/tmp/test-repo')
|
||||
local hunks = parser.parse_buffer(bufnr)
|
||||
|
||||
assert.are.equal(1, #hunks)
|
||||
assert.are.equal('/tmp/test-repo', hunks[1].repo_root)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
|
||||
it('repo_root is nil when not available', function()
|
||||
local bufnr = create_buffer({
|
||||
'M lua/test.lua',
|
||||
'@@ -1,3 +1,4 @@',
|
||||
' local M = {}',
|
||||
})
|
||||
local hunks = parser.parse_buffer(bufnr)
|
||||
|
||||
assert.are.equal(1, #hunks)
|
||||
assert.is_nil(hunks[1].repo_root)
|
||||
delete_buffer(bufnr)
|
||||
end)
|
||||
end)
|
||||
end)
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue